Section 176. “Weight” in a sale of commodities by weight shall mean the net weight of all commodities so sold; and contracts concerning such sales shall be so construed; provided, that in respect to commodities not intended for food or fuel reasonable tolerances or variations shall be permitted in accordance with established trade customs. As defined in section one, ready-to-eat food sold from bulk or in single servings packed on the premises, may be sold by weight, measure or count; provided, however, that count shall include servings. Violation hereof shall be punished by a fine of not more than one hundred dollars or shall be subject to a civil citation as provided in section 29A of chapter 98.